The present invention is directed to a sortation system and method and, in particular, to a sortation system and method in which product is supplied from a plurality of feed lines, such as accumulation lines or slug-building lines, and merged with a merge assembly.
In a material-handling system, it is common for product to be supplied from various sources and combined at a merge assembly. In such a system, the product may be accumulated upstream of the merge, such as in a plurality of slug-building lines in which the product is combined into slugs. An example of such a system is a system in which product is picked, manually or automatically, at multiple locations, each of which feeds a feed line. Alternatively, the product may be off-loaded from trucks at numerous docks and supplied to the feed lines.
The outputs of the feed lines are combined at a merge assembly and transported to a sortation assembly. The feed lines discharge product in a particular sequence to the merge assembly where they are combined and transported to the sorter assembly.
One difficulty with such material-handling system is that the performance curve of the sorter assembly and the performance curve of the merge assembly are typically different. Reference is made to FIG. 1. The merge assembly typically supplies fewer products than the sorter can sort with larger carton sizes and feeds more product than the sorter can sort with smaller carton sizes. While this would not typically be a problem if a unitary product size is handled by the material-handling system, most material-handling systems are required to handle a range of product sizes. As such, it is difficult to match the rate of the merge assembly with the rate of the sorter assembly resulting in either too much product or too few product being supplied to the sorter assembly at any particular time.